Penicillin G Overview and Mechanism

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Questions and Answers

What can accidental injection into a peripheral nerve result in?

Tissue necrosis

Seizures

Motor dysfunction (correct)

Gangrene

Why should clients with a PCN allergy avoid cephalosporins?

There is a low risk of cross-sensitivity. (correct)

They cause more intense allergic reactions.

They are always ineffective against bacteria.

They may cause increased renal impairment.

What is the recommended dosing interval for adults receiving PCN G?

At 4-hour intervals (correct)

Every 2 hours

Every 12 hours

Once daily

What should clients on sodium-restricted diets be cautious of?

Sodium PCN G Signup and view all the answers

Which type of agents should be avoided in conjunction with PCNs due to reduced efficacy?

Bacteriostatic agents Signup and view all the answers

What may renal impairment cause regarding PCN dosing?

An increase in its half-life Signup and view all the answers

What is important for clients to understand about their treatment with PCN?

They must complete the full course of treatment. Signup and view all the answers

Which of the following may occur due to neurotoxicity from PCN?

Hallucinations Signup and view all the answers

What is the primary function of penicillin G?

It weakens the bacterial cell wall leading to cell lysis. Signup and view all the answers

Which infections is penicillin G primarily used to treat?

Infections caused by gram-positive cocci. Signup and view all the answers

What mechanism allows penicillin G to be bactericidal?

It inhibits transpeptidases and disinhibits autolysins. Signup and view all the answers

Which of the following is NOT a therapeutic use of penicillin G?

Treatment of viral infections. Signup and view all the answers

For which of the following conditions is penicillin G the drug of choice?

Meningitis caused by N. meningitidis. Signup and view all the answers

What is a common adverse reaction associated with penicillin G?

Hypersensitivity reactions. Signup and view all the answers

Which of the following statements about penicillin G is true?

It remains the drug of choice for many infections. Signup and view all the answers

What role does penicillin G play in rheumatic fever management?

It is used for prophylaxis and treatment of recurrent cases. Signup and view all the answers

Study Notes

Penicillin G (Benzylpenicillin) Overview

Category: Narrow-spectrum penicillin
Primary Function: Active against gram-positive bacteria, gram-negative cocci, anaerobes, and spirochetes. First-line treatment for infections caused by sensitive gram-positive cocci.
Unique Feature: First available penicillin, remains a choice for many infections.

Mechanism of Action

Weaken bacterial cell walls, causing excessive water uptake and rupture.
Achieved through inhibition of transpeptidases and disinhibition of autolysins.
Effective only against bacteria undergoing growth and division.

Indications and Therapeutic Uses

Gram-positive cocci infections: Treatment of choice for Streptococcus pneumoniae, pharyngitis (Strep. pyogenes), and infectious endocarditis (Strep. viridans).
Gram-positive bacilli infections: Preferred for gas gangrene, tetanus, and anthrax.
Meningitis: Treatment for Neisseria meningitidis infections.
Gonorrhea: Effective against non-penicillinase-producing strains of Neisseria gonorrhoeae. (Alternative treatment now available for other strains).
Syphilis: Treatment of choice for syphilis. Also used for prophylaxis (prevention) of exposure partners.
Rheumatic fever: Prophylaxis and treatment of recurrent rheumatic fever.
Bacterial endocarditis: Prevention and treatment in clients with prosthetic heart valves, congenital heart disease, acquired valvular heart disease, mitral valve prolapse, and a history of bacterial endocarditis.

Side Effects and Adverse Reactions

Hypersensitivity: Most concerning; also consider cross-reactivity with cephalosporins.
Injection site reaction: Pain, injection site irritation, including potential for nerve damage.
Neurotoxicity: Seizures, confusion, hallucinations (with toxicity).
Drug Interactions: Concurrent use of bacteriostatic agents (like tetracyclines) might reduce penicillin's effectiveness and should be avoided.

Precautions and Contraindications

Allergies: Clients with a penicillin allergy should be considered allergic to all penicillin-based agents.
Cross-sensitivity: Due to potential cross reactions with cephalosporins to be cautious if there is a history of allergy.
Sodium restriction: Caution is advised with sodium-restricted diets.

Dosing, Administration, & Client Teaching

Dosing: Varies based on the condition, severity, and client response.
Administration: Intramuscular (IM), intravenous (IV).
Monitoring: Assess for hypersensitivity reactions, closely monitor renal function (e.g., BUN/Creatinine, creatinine clearance) for adjusting dosages.
Client Education: Educate clients on the importance of completing the full course of treatment as prescribed, and encourage them to report any side effects.

Labs to Monitor

Basic Metabolic Panel (BMP): Assess renal function, as renal impairment can increase the half-life of penicillin, impacting dosage and increasing the risk of toxicity.

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Description

Explore the functions, mechanisms, and therapeutic uses of Penicillin G, a crucial narrow-spectrum antibiotic. This quiz will assess your understanding of its application against various bacterial infections, particularly gram-positive cocci. Test your knowledge on how it works and its significance in treating specific diseases.